SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

The Hunter Mini-Cliks and the Rain Bird RSD Rain Sensors are both very good rain shut off devices. They both work using the same technology. They both shut off the sprinklers in a storm and keep them off, automatically compensating for the amount of rainfall that occurred. Disks absorb water and then expand proportionally to the amount of rain that fell (e.g., a small cloudburst would result in little absorption, a thunderstorm with 6" of rain would lead to more absorption and thus more expansion). As the moisture-laden disks expand, they eventually activate a switch that interrupts the circuit from the controller to the solenoid valves. Once dry, they contract and release the switch. Thus, the rain sensors automatically reset without ever affecting your controller.
Both rain sensors can be used on any brand controller. The difference is that the Rain Bird RSD rain shut off device is a more newly developed product and has more than 20 rainfall settings from 1/8 inch to 3/4 inch and has an adjustable vent ring which helps control drying time. The Hunter mini-Clik has 5 settings from 1/8 to 1 inch and does NOT have an adjustable vent ring.
An older rain sensor product is the Rain Bird RainCheck rain shutoff device which catches water in a cup an has adjustable stainless steel sensing probes that offer the flexibility of triggering the rain shutoff with as little as 1/8" of precipitation or when rainfall reaches or exceeds 1/2". The problem with the RainCheck is that leaves and debris can fill the cup also, which means you have to dump the cup out every so often.
I suggest the new Rain Bird RSD or the Hunter Mini-Clik, both works exceptionally well.
The moisture evaporates from these devices at a very similar rate as the moisture evaporating from the soil. When the soil begins to need water again, the sensors should be dry enough to allow the controller to resume it's scheduled watering times.
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Definatly use the Hunter Mini-Click